Yup, MinHash with LSH. It's quite fast and low compute intensive, because articles shown are limited by recency (e.g. past 24 hours), say order of hundreds and thousands in a few seconds. Someone wrote an open source LSH on github on Golang, so no credits to me :) Probably would not have been able to code LSH myself.
It would be awesome if you blogged about your entire experience setting up your news aggregator. But I guess your first priority is PageDash these days so I can keep dreaming. :-)